Thermoelectric research in CSIRO

Thermoelectrics Capabilities CSIRO Materials Science and Engineering (CMSE)

Dr. Nick Savvides, Dr. Karl Müller, Dr. Haiyan Chen, Jack Ling, Dr. Dong Chen, Sarah Miller, and Dr. Howard Lovatt

CSIRO. Thermoelectric Capabilities

Motivation

•  Figure of merit for thermoelectrics •  Current best materials have ZT ~1 •  Typical system efficiency 5 - 12% •  ZT ~ 2 would give up to 25% efficiency •  (For reference, current combustion engine efficiency ~25%!)

1200 1000 800 600 400 200 0 Temperature (K)

ZT: f

igur

e of

mer

it 1.0

0.8

0.6

0.4

0.2

0.0

Si1-xGex PbTe

BiSb

Bi2Te3

Room temperature

TZTκσα 2

=


Materials Research

•  Aims of present work •  Prepare fine Mg2Si, Mg2Ge, Mg2Sn and their solid solutions •  Characterize the microstructure, TE prop: α, σ, κ •  Optimize ZT by nanostructuring …..

•  Processing •  Ingots & single-crystals

•  direct-melting, Bridgman method, zone-melting… •  Dense compacts:

•  Reduction to nano-powders, mechanical alloying, hot pressing…

•  Characterization •  Microstructure & composition: XRD, SEM, TEM, EDX… •  TE properties: Seebeck, resistivity, thermal conductivity …. •  Device assembly & testing…..


Mg2Sn

αx

Isotropy αy

Seebeck Coefficient

Compound Literature CSIRO

Mg2Si 200 – 500 µV/K 330 – 350 µV/K

Mg2Ge 200 – 700 220 – 360

Mg2Sn 20 – 115 135 – 188


Electrical Conductivity

Dramatic increase in electrical conductivity with control of eutectic composition


Theoretical Materials

Motivation •  No theoretical limit to performance •  Recent reports of experimental

materials with high ZT


Molecular Quantum Dot

0D ~1 nm

Nanoparticle Electron Reservoir

~100 nm

Theoretical Materials

Result •  CSIRO has a provisional patent on a novel material - offers high ZT ~10


Genset Waste Heat Recovery

•  30 kW natural gas Genset

•  Waste heat from exhaust 18kW •  Target electricity 500W

•  FY 07/08: Demonstration unit

Pump

Boile

r

Expander

Con

dens

er

Water Heater

85°C90°C

95°C

5.4 L/min

+17kW

+17kW

-34kW +34kW -30kW

520°C 150°C

Pump

Boile

r

Expander

Con

dens

er

Water Heater

85°C90°C

95°C

5.4 L/min

+17kW

+17kW

-34kW +34kW -30kW

520°C 150°C

Pump

Boile

r

Expander

Con

dens

er

Water Heater

85°C90°C

95°C

5.4 L/min

+17kW

+17kW

-34kW +34kW -30kW

520°C 150°C

Thermoelectric

Electric Output


TEG System in Construction


Solar Thermoelectric Design and Analysis

• Motivation: To design and evaluate solar thermoelectric systems suitable for urban, rural and remote locations

•  Facilities and Capabilities: •  The National Solar Energy Centre in Newcastle has tracking solar

collector systems including parabolic troughs and heliostat array. A solar dish is located at Lucas Heights

•  The National Solar Energy Centre continuously records accurate local weather data for system analysis

•  Design and analysis of solar thermal systems using the latest tools and techniques developed by, and in collaboration with, the international solar thermal community

•  Multidisciplinary team of physicists, electrical, electronic, mechanical and chemical engineers with expertise in optics, fluid dynamics and thermodynamics


Concentrating Solar Facilities


DET Thermoelectric Activities

•  Engaging with major engineering company on feasibility of harnessing energy from the environment, including a low temperature, non-concentrating, solar powered thermoelectric device ($70k)

•  Performing an techno-economic appraisal of a solar thermoelectric trough concept

•  Evaluating technologies for harnessing energy from the environment to power sensors. Literature review in progress


Power Conditioning and Control

Power generation •  Convert/invert voltage •  Need to find maximum power point and convert/invert voltages


Applications

• Medical hyperthermia/hypothermia •  Energy conservation • Waste heat energy recovery •  Sensing •  Refrigeration •  Solar thermal power generation

Thank You

Contact Us Phone: 1300 363 400 or +61 3 9545 2176

Email: [email protected] Web: www.csiro.au

CSIRO Material Science and Engineering (CMSE) Dr. Howard C Lovatt Stream Leader - Energy Conversion Devices

Phone: +61 2 9413 7412 Email: [email protected] Web: www.csiro.au

Technology

Thermoelectric research in CSIRO